1 Topic by Spank (edited by Spank 2011-03-08 08:45 PM)

  • Spank
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  • From: Escondido, CA
  • Registered: 2009-06-10
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Topic: Dinky turbo help?

Our turbo-knowledgeable teammate seems to think our turbo has lost a carbon seal, likely has a damaged shaft and/or bearings, and will not survive another race.

We have some wiggle room in our residual and are looking at options.

For those who understand this stuff,  Our turbo is a this one:

http://www.turbofast.com.au/img/t3-40.JPG

Here's a link to an exploded view and other data I don't understand:

http://www.melett.com/turbo-buildsheet- … no=CAM6924

Garrett Part number is TBO329

He seems to suggest that a KO3 for a VW (via ebayChina or someone's take-off) would work for us. I just want something that will perform similarly to what we've already got, running 7-10ish psi of boost with good feel from 3500-6000rpms  My Butt dyno says our 998 cc engine had about 70-75hp after adding the turbo. No need to supply anything more than that.

Someone else suggested a GT1752 off of a Saab.

Any of you who are smart with turbos able to offer suggestions/advice?

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  • From: Sacramento
  • Registered: 2010-08-09
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Re: Dinky turbo help?

turbo off a twin-turbo 300zx would be good for a 1500cc. It's a T3 and not particularly high revving.

I have a frozen one and one that spins, but was going to be putting it on a certain GT5 car.

~got both for $55.

If you can figure out what's wrong with the frozen one...

  • From: Baltimore, MD
  • Registered: 2010-05-20
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Re: Dinky turbo help?

Turbo I K-engines usually (except 2.2L's in 1988) wear a Garret T03 - which has the exact same compressor map as your current one.

Assuming you meant your current turbo's P/N is TB0329, that's because it's the exact same unit.

K-cars are common as hell, surely you can find a turbo one and loot it on the cheap.

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  • Spank
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Re: Dinky turbo help?

Ok, so I've got a turbo from a 2.2 shelby and it's 466298-0004 which googles to a TB0335. The A/R is 0,48 whereas our current unit, the TB0329 has an A/R of 0,25

That other turbo is going to spool up a lot slower, no? the turbo we're using was for a 1.3 liter car. We're already using it on a 1 liter car... Shooting up to a 2.2 liter car's turbo-- wouldn't that bring things on even later? Will our dinky motor even be able to spin it before 5K?

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  • From: Sacramento
  • Registered: 2010-08-09
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Re: Dinky turbo help?

Spank, I know - tech stuff you enjoy oh-so-much... but here it goes:
It is possible to design an exhaust that will get it to pick up quick - but the word DESIGN is heavy. Yeah - the "advertised" .48 will be a later hit on the r's - but the a/r# isn't enough info to really tell.

The better way to ghetto-size you are already doing - what engine and Rev range did it come off of compared to what it is going on. yours is not an exact or close match, so...

The 2.2 shelby has medium sized exhaust ports for its displacement and valve size.
It has a 4-1 merge manifold. This will not make quite the velocity of a 4-2-1 at the turbo location

Your  stock mini has small ex ports for its displacement
the 2-3 is shared and a bit big - the 1&4 ports are high velocity.

If you make a small-bore manifold such that each port aims at the outer part of the turbine wheel, and such that the pulses are timed to hit sequentially, you could get a modest boost with relatively early-on with the 2.2's turbo.

~to do this, keep all exh tubes small - as in the size of the 1-liter 3-1 header.
~make all tube equal length, make sure the middle one necks down to the same size as the outers. Ideally this length will be such that the volume of a single pipe is about 1/3 to 2/3 the volume of a cylinder pulse where the turbine is being hit during a cycle. (many reasons here)
~design the attach-plate so that the three tubes aim directly at the outer portion of the turbine vanes - if the tubes go into the turbo port a wee bit this will help.
...on the intake side of the turbo - a cone from the large outlet to your inlet might be good - this will reduce turbo stall that can be an issue with a sudden-size-change reducer.

You are looking to retain exh gas VELOCITY frm the valve exit to the turbine wheel.

you are wanting to keep the compressor spinning w/o sudden fluctuation and back pressure so need a smooth transition from the compressor exit to the valve. (This is actually a invert parabola like a trumpet-type ram-pipe, but a straight cone is OK)

MUCH WORK.

  • From: Gilbertsville, PA
  • Registered: 2009-12-22
  • Posts: 3,252

Re: Dinky turbo help?

crazymike wrote:

Spank, I know - tech stuff you enjoy oh-so-much... but here it goes:
It is possible to design an exhaust that will get it to pick up quick - but the word DESIGN is heavy. Yeah - the "advertised" .48 will be a later hit on the r's - but the a/r# isn't enough info to really tell.

The better way to ghetto-size you are already doing - what engine and Rev range did it come off of compared to what it is going on. yours is not an exact or close match, so...

The 2.2 shelby has medium sized exhaust ports for its displacement and valve size.
It has a 4-1 merge manifold. This will not make quite the velocity of a 4-2-1 at the turbo location

Your  stock mini has small ex ports for its displacement
the 2-3 is shared and a bit big - the 1&4 ports are high velocity.

If you make a small-bore manifold such that each port aims at the outer part of the turbine wheel, and such that the pulses are timed to hit sequentially, you could get a modest boost with relatively early-on with the 2.2's turbo.

~to do this, keep all exh tubes small - as in the size of the 1-liter 3-1 header.
~make all tube equal length, make sure the middle one necks down to the same size as the outers. Ideally this length will be such that the volume of a single pipe is about 1/3 to 2/3 the volume of a cylinder pulse where the turbine is being hit during a cycle. (many reasons here)
~design the attach-plate so that the three tubes aim directly at the outer portion of the turbine vanes - if the tubes go into the turbo port a wee bit this will help.
...on the intake side of the turbo - a cone from the large outlet to your inlet might be good - this will reduce turbo stall that can be an issue with a sudden-size-change reducer.

You are looking to retain exh gas VELOCITY frm the valve exit to the turbine wheel.

you are wanting to keep the compressor spinning w/o sudden fluctuation and back pressure so need a smooth transition from the compressor exit to the valve. (This is actually a invert parabola like a trumpet-type ram-pipe, but a straight cone is OK)

MUCH WORK.

Huh?

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7 Reply by jrbe (edited by jrbe 2011-03-09 05:34 AM)

  • jrbe
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  • From: Central CT
  • Registered: 2009-06-23
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Re: Dinky turbo help?

A K03 would be a downsize your t3 turbo.  This could be a good thing if you can up the boost a bit to make up for it.  Basically it will come on earlier but could fade off a bit in the upper rpms.  Though, with a 1.0L 50-ish hp stock engine im not sure fading off would be possible.  A k03 can make about 220hp maxed out on a high flowing engine.
  They come on very early on a 1.8 and can make a flat torque peak (which means full spool at 2200rpm) on a 1.8 from 2200-5500rpm.

Engine size doesnt always give the best clue on turbo sizing.  Hp curve to turbo size can be a more useful

K03's are a pretty commonly failing turbo.  Largely from overboosting with junk chips (ecu tune,) from oil coking in the turbo from not being changed regularly, or boost leaks making the turbo spin way too fast.  Lots of shadyness selling these used like its fine, no smoke but shaft play tells a different story.  You can get rebuild kits though they are hard to find and the turbos are fragile.  Soak the compressor nut for a while before you try to remove it.  I believe the shaft is 4mm, go easy!

You can search compressor flow calculator or compressor map calculator and input #s for your engine.  If you can figure this out it can help size the ideal turbo if you input everything correctly, http://www.turbofast.com.au/turbomap.html there are instructions below.  This only has garrett maps though.

You can get your ve by using 0 as boost and moving VE around to get non turbocharged hp match stock hp curve.  Then play with boost to get hp where you want.  You then can flip through maps to see where the efficiency ends up for that turbo map.

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  • jrbe
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Re: Dinky turbo help?

You can take your turbo apart too and rebuild it unless something is damaged.  Why not pull it apart and see?  Its not too bad, just be careful.  Make sure the repair kit has a carbon seal if thats what you need.

-Killer B's (as in rally) '84 4000Q 4.2V8. Audis never win?
  • From: Shakopee, MN
  • Registered: 2009-10-05
  • Posts: 136

Re: Dinky turbo help?

Mitsubishi has a few turbos on the smaller side. The stock T25 turbo for 2nd generation Eclipse and such are a good choice. The twin turbo 3000GT has an even smaller turbo that may work better.

I guess it depends on what exhaust flange you want.

  • From: Rockville, MD
  • Registered: 2010-12-15
  • Posts: 1,155

Re: Dinky turbo help?

Our CA18DET has a T25 that supposedly pumps nothing but hot air by the time it hits 180hp. If you get your hands on an OK T28 or something or other, we'll swap with you wink

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  • From: Romeoville, IL
  • Registered: 2009-12-12
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Re: Dinky turbo help?

I would be looking for a T25 size turbo for an engine that small.

T25's on 87-89 300zx turbos are especially worthless and free from the right source.

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  • From: Hayward, CA
  • Registered: 2010-03-23
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Re: Dinky turbo help?

Spank wrote:

Ok, so I've got a turbo from a 2.2 shelby and it's 466298-0004 which googles to a TB0335. The A/R is 0,48 whereas our current unit, the TB0329 has an A/R of 0,25

The A/R (area Ratio) determines how the turbo .. responds to the exhaust gases on the turbine side (hot Side) and the on the compressor side, how it compresses the intake air.

Small A/R wheels in the turbine tend to spin up faster. For a given engine a .25 A/R will spin up faster than a 0.60 A/R. But the Small A/R will max out in speed vs exhaust sooner.  If you draw your volumetric flow rate on the turbo map (have to calculate how much air your 998cc engine sucks av various RPM) you'll see at some point for a small turbo, you will go to the right and off the map. That means the turbo is maxed out and providing all it can provide.

Similarly, on the compressor side a small turbo wheel will start to pressurize sooner vs a big wheel. But the small wheel will also reach its limit and then you'll hit the surge line (left edge). The bigger turbo wheel will spin up slower, but when it starts to make pressure, it will make more pressure.

So the idea (if your doing this correctly) is to a) figure out the RPMS you want to have boost for, b) figure out the volumetric flow rates, C) pick a turbo and plot the V flow to see where you land. Optimally you want to go right through the middle of the bullseye of the map and not hit the Surge line or fall off the map to the right. If the "map" is not wide enough (you fall off the curves to the right), you need to go to a bigger turbo. If the map is too wide, smaller turbo. If you hit the surge line, right size, different A/R. etc........

For Lemons you'll want mid range boost, that should probably max out just below redline, unless you run your engines to redline (YEAH baby, BOOM!), So a smallish turbo is better than a big Turbo. I would just guess that a T3 is too big for your 1 Liter. Try looking for Diesel engined turbos, since they are designed to spin up a lower Engine volumetric (lower RPM) ranges

Try running this online calculator for your engine and the different turbos. You'll have to fool it a bit on injector size (just put in 280cc or bigger)
http://www.squirrelpf.com/turbocalc/

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  • From: Hayward, CA
  • Registered: 2010-03-23
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Re: Dinky turbo help?

P.S. I just ran the turbo calculator and for a 1 liter 110 Hp engine, Redline of 7K,

The T1241 would be OK,
The T1544, T1548 should work pretty good,
and surprisingly, the T3 in 0.40 A/R Trim looks like a good match too.
The K03 -1870 looks good
Ko3-2075 and Ko3-2072 OK

You just have to flow enough fuel to make 110 hp!!!


For only 70 Hp same 1 liter and 7 k redline, most off those turbos are too big, your on the bottom edge of the turbo map. the K3-1870 was probably the best fit for only 70 hp.

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  • Spank
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Re: Dinky turbo help?

Our redline will be 6500, and 110 hp is being very optimistic. Our first motor was a high compression build with a reground cam and it put out 52hp. But that is now broken, repaired and is our backup motor.

But the stock motor is more along the lines of 42hp. At the flywheel. I'd say that's our starting point-- maybe a couple more since we're using a stock 1275cc cam and head on our 998cc block. The TB0329 is for a 1.3 liter car that ran 7psi boost and was rated at 100hp from the factory. Some of the guys I've found who are boosting these same 998 engines run a T2 or a T1.5 or T1.7 but they are going for fast spool road use or 1/4 mile cars I think.

Our TBO329 does indeed fall off boost if you go much below 3500, but the budget valvetrain can't really handle more than 6500rpms for endurance racing, as we've found. I'm ok with the 3000-3500 low point because it helps save the transmission (ANOTHER weak point in our car-- plus the cooling, the 3 bearing mains, the engine and transmission sharing the same oil, etc).

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  • From: Gilbertsville, PA
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Re: Dinky turbo help?

Can't you just use a small rodent on a wheel chasing a nut to help spool your 1" impeller?

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  • Spank
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Re: Dinky turbo help?

Sir Thomas Crapper wrote:

Can't you just use a small rodent on a wheel chasing a nut to help spool your 1" impeller?

We've already got 4, each moving one of our 2.54" dia pistons, which I think is the maximum number of rodents permitted under the new 2011 rules

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  • From: Gilbertsville, PA
  • Registered: 2009-12-22
  • Posts: 3,252

Re: Dinky turbo help?

That rulebook is getting as thick as the SCCA's!

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  • From: VA
  • Registered: 2010-05-05
  • Posts: 920

Re: Dinky turbo help?

I skimmed the thread.  a .48 a/r T3 turbine housing is going to spool slow/late on a 1000cc engine.  Whatever you have now is probably sized about right.

Find a small turbo from a small displacement gas engine, or maybe a small passenger car diesel engine.  Newer VW stuff is probably more in line with what will work.  Or one from a twin turbo 6.  I think the Volvo S80 T6 engine has turbos that bolt to the manifold (as opposed to some where the turbine housing is integrated into the exhaust manifold).  The S80 T6 kills the auto trans all the time and I'm starting to see them at the u-pull-it junkyard.

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  • From: Sacramento
  • Registered: 2010-08-09
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Re: Dinky turbo help?

Still going to say The 300ZX turbos are still the best cheap-shot for most-common small turbo... I think they're a T25, and are pretty cheap - problem is most peeps toss' them rather than craigs them.